Compactlogix Output Speed

Big John T · Apr 8, 2008

There doesn't seem to be any highspeed outputs for the CompactLogix line. What would the output speed be for a normal 1769-OB16? It doesn't seem to say in the manual...

Thanks
John

widelto · Apr 8, 2008

From the AB manuals I got this for the 1769-OB16:

Signal On Delay, Max (resistive load) 0.1 ms

Signal Off Delay, Max (resistive load) 1.0 ms

Big John T · Apr 8, 2008

Thanks Bill.

I must have overlooked that. Kinda slow for what I want.

Thanks
John

Eddie Willers · Apr 8, 2008

Remember that the RPI rate on CompactLogix backplanes varies with the controller. The 1769-L32E, for example, updates the CompactBus every 5 milliseconds, configurable down to 1 millisecond.

If you need outputs that react faster than 1 millisecond, you're probably outside the capabilities of a general-purpose logic controller algorithm.

What's the application ?

OZEE · Apr 9, 2008

Big John T said:
Thanks Bill.

I must have overlooked that. Kinda slow for what I want.

Thanks
John

Kinda slow?? That's gotta be faster than any device it might be activating...

As has already been asked -- what's your application??

Big John T · Apr 9, 2008

Drive a servo controller with step and direction signals.

Thanks
John

Hundikoer · Apr 9, 2008

Big John T said:
Drive a servo controller with step and direction signals.

Thanks
John

Doesnt sound good...

Big John T · Apr 9, 2008

I'm going to use the panasonic with 100kHz outputs and electronic gearing to drive it.

John

CroCop · Apr 9, 2008

John,

That's a motion application, not a general purpose IO application.

Panasonic, Automationdirect, & many others have that function built right in the controller base IO, but the Compactlogix does not.

kolyur · Apr 9, 2008

I think this was suggested in another thread but have you looked at the AMCI stepper controller? It can output a pulse train up to 1 MHz.
http://www.amci.com/stepper-motor-control/compactlogix-stepper-motor-controller.asp

I haven't used it but am planning to in an upcoming project. I have read a number of positive comments about it. I also heard that AMCI makes the servo and stepper modules that Allen-Bradley sells for the SLC.

Big John T · Apr 9, 2008

kolyur, yes I looked at the AMCI.

You would think that with Motion build in the CompactLogix you would have some high speed I/O...

John

widelto · Apr 9, 2008

John:

Try compactlogix 1768-L43, then add a sercos interface module and make sure that your panasonic drive is also sercos compatible, the your problems are solved.

Eddie Willers · Apr 9, 2008

NO, no, no. A-B motion control over SERCOS works only with A-B motion controllers like the Ultra 3000 or the Kinetix series.

I've seen a tiny handful of OEMs get A-B to create a custom SERCOS profile for specific 3rd party drives, but that's an expensive and complex method.

You can do some step-and-direction with the MicroLogix 1500 because its I/O base includes a dedicated purpose output circuit for that. If you have a step-and-direction servo controller that you want to use with CompactLogix, you need an AMCI card.

Big John T · Apr 9, 2008

For $200 I'll use the panasonic plc. Everything else seems to be a work around.

Thanks for all the input
John

Compactlogix Output Speed

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